Troweling machine



May 3, 1949. J. o. HUFFMAN 2,463,981

TROWELING MACHINE Fild Oct. 29, 1946 i 2 Sheets-Sheet 1 M ATTQQAEKPatented May 3, 1949 UNITED S TATES PATEN 2,468,981

TROWELING MACHINE James 0..Hufiman, Los,Angeles,@Calif-.. ApplicationOctober-'29, 1946, Serial No. 706,479

4 Claims.

1 Myinvention relates generally to troweling machines adapted for -usein smoothing and finishing concrete floors, driveways, and other fiatsurfaces. Specifically, the invention pertains to a troweling machinehaving a plurality of rotary mover, and in which the trowel members areadapted to be inclined at various angles with respect' to the surface ofthe concrete mass to effect a rough troweling and a finish troweling ofthe mass.

Another object is to provide a machine of the type indicated in whichthe angularity or inclination of the trowel members is controlled by thespeed .of rotation of the trowel members, so that by varying the speedof the prime mover the inclination of the trowel members may be variedautomatically in accordance with the requirements,.and thus thenecessity of providing separate manually-operated means for adjustingthe setting of the trowel members is avoided.

Another object is to provide in a machine of theclass specified havinggovernor means responsive to change in the speed of the prime mover forautomatically changing the inclination of the trowel members.

Another object is to provide a portable troweling machine which isrelatively simple in construction, easily operated, and highly efficientin performing its intended function.

Further objects of theinvention are set forth in.the followingspecification, which describes several preferred embodiments of themachine, by way of example, as illustrated by the accompanying.drawings. In the drawing:

Fig. 1 is a plan View of my improved troweling machine;

Fig. 2 is an enlarged side elevation of the machine,.shownpart-sectional online 2-.2 of Fig. 1;

Fig. 3 is a verticalsectional view, taken on line 3-3 of Fig. .1, andillustrating one of the trowel members as inclined to a slight angle;

"Fig. 4 is a view similar to Fig. 3 but showing the trowel member tiltedto a greater angle;

Fig. 5 is a plan view of the lower part of the machine, shownpart-sectional on line 5--5 of Fig Fig. 6 Ba sectional view, takenonline 6-6 of Fig.2;

Fig-"l is a cross-sectional view-of the lower part 2 of the machine,showing an alternative means for effecting adjustment of the trowelmembers; and,

Fig. 8 shows an-alternative-means for tilting the trowel members.

Referring first to 'Figs. 1 to 6 of thedrawings, my improved trowelingmachine includes a circular box-like housing H whichis'supportedslightly above the floor or other surface to be troweled bythe trowel members H in the manner to be later explained. The-housing l0has'a removable cover 12, andfastened to-the-cover is-a drive-plate l3having 'acentral tubular spindle l4. Surrounding the-spindle II, withitsendresting upon the drive-plate 13, ha boss l6 forming part'of agear-boxorcasing-FI to which a handle I8 is secured, saidhandle-providing a meansfor pushing, pulling, and guiding the machinealong the concrete mass, ,it'being noted that the trowel members I Irest 'directlyuponthe concrete mass;

Fastened to the open upper end of the casing I1 is a plate ML-whichforms the base of a frame 2| which "supports a prime'mover 'or powerunit 22, which may be an internal combustion engine or an electricmotor. The power'unit22 is adapted to rotate the housing 10 and trowelmembers H through driving connections to be next described. Keyed to thetubular spindle I4 is a worm wheel 25, which is adapted to be rotated bya worm 26 fast on a horizontal shaft 21 'journaled in bearings in thecasing 11. The shaft 21 projects beyond one side of the "casing l1 andcarries a grooved pulley 28, which is driven from a grooved pulley 29fast onthe output shaft '30 of the power unit 22 by means of aV-belt 3I. When the shaft 30 is driven, rotary motion is transmitted to thespindle l4 through the medium of the pulleys 29 and 28, belt 31, worm2B, and worm wheel 25, and the housing 'l'fland trowel members II arethus rotated with respect to the concrete mass. The speed of the powerunit may be controlled by a suitable throttle or rheostat, as shown atH10 in Fig. 2.

Any suitable number of rectangular plate-like trowel members Il may beprovided, and each member is carried by a shaft 35 which projectsradially from the housing [0 and which is adapt.- edto oscillate insuitable bearings 36. The outer reduced ends of the radial shafts 3,5are adaptedto turn in brackets 31, which are fastened'to .a guard ring38' arranged concentric with the axis of rotation of the housing It.Referring to Figs. 2 and 5, which show only three trowelingmembars, theshafts35 carry bevel-gears 40 at their inner ends within 'theiious'ingl0, the' bevel gear 40" of one shaft 35 constituting the drive gear and.the bevel gears 40 of the other shafts 35 each meshing with this drivegear. The several gears 40 and 40' are keyed to their respective shafts,and are normally held in meshing engagement by springs 42. The shaft 35'and its trowel member II are adapted to be turned by means to be nextdescribed, and the turning movement of the shaft is transmitted to theother shafts 35 through the meshing bevel gears 40 and 40, so that allthe trowel members are tilted simultaneously in the same direction andto the same degree. The shaft 35' is adapted to be turned automaticallyby means to be next described.

The shaft 35 is provided with an arm 43 having a roller i l at its end,which is engaged by a finger 45 pivoted at 46 within the housing Iii andresting against the roller. The finger 45 is adapted to be pivoteddownwardly to depress the arm l3 and turn the shaft 35' in clockwisedirection, as viewed in Fig. 2, by means of a plunger 48 slidablevertically in the bore of the tubular spindle M with its lower endresting upon the finger. The plunger 18 may be made in two parts, asherein shown, with the lower part, des" ignated t8, slidably mounted inthe cover plate I2, so that other travel assemblies of different sizes,or other attachments, may be substituted for the one illustrated, suchassemblies, or attachments, also having short plunger parts which may beinserted into the lower end of the spindle I4. The construction is suchthat attachments may be connected to the drive plate is withoutinterfering with the plunger it. When the plunger 58 is forceddownwardly, its lower end 48' engages with and depresses the finger dtending to tilt the same in order to rotate the shaft 35', whereby thetrowel members are tilted. A coil spring it is provided to rotate theshaft 35 in the same direction, and serves as a preloading means to aidin overcoming the weight of the machine when resting upon the trowelmembers. One end of the spring is connected to a stud 5t, adjustablyscrewed into a role in the side of the housing ill for varying theaction of the spring.

The plunger 43 is depressed by one arm 52 of a bell-crank lever 53pivoted at 5 3 to a bracket 55 projecting laterally from the frame ii.The bell-crank lever t3 has a substantially vertical arm 56 having anupper yoke end, the sides of which carry rollers 5i engageable in theopposite sides of a peripheral groove 58 formed in a collar iii-lslidably mounted on the shaft 3i). Pivoted at 69 to the collar til arearms 52 having their outer ends pivoted to similar arms 63, which, inturn, are pivoted at M to the hub of the grooved pulley 25. At the outerpivoted ends of the arms 62 and ii? are weights $5, which are adapted tomove radially outward under the influence of centrifugal force to movethe collar Ell toward the pulley 29 against the action of a spring 68interposed between the collar and pulley.

The collar 6%, arms is? and t3, and weights 65 constitute a governor 51,and when the speed of the power unit is increased by manipulating thethrottle or rheostat toward the maximum position, the governor actsthrough the bellcrank lever 53, plunger 48, finger 45, and arm 43 toturn the shaft 35, together with the shafts 35, to tilt the severaltrowel members it from the position shown in Fig. 3 to that illustratedin Fig. 4. Conversely, when the speed of the power unit is decreased,the weights 65 of the governor 6'! will be moved inwardly by the spring55, and, through the instrumentalities above described, the shafts 35'and 35 and the several trowel members ii will be moved to the positionshown in Fig. 3 by the weight of the machine when resting on the trowelmembers.

It will be understood that when the trowel members are in the relationshown in Figs. 3 and 4 they are adapted to perform various trowelingoperations from the rough troweling for forcing the stones or aggregatedown into the concrete mass, to the finishing of the concrete, or othermass.

Referring now to Fig. 7 of the drawings, my invention contemplates theprovision of an alternative means for effecting the turning of the shaft35'. In this modified structure, the governor mechanism, the bell-cranklever and the plunger, and associated parts described in connection withthe embodiment illustrated in Figs. 1 to 6 are dispensed with and asimplified means employed for the purpose. The housing has a radiallyextending cylindrical chamber iii formed in its side wall, and slidablein the chamber is a weight H which is connected to a pulley it! by acord or cable 13. The pulley formed on a stud-shaft i i having ascrewthread of steep pitch adapted to be screwed up and down in avertical hole in the drive plate it. When the speed of the power unit 22is increased, the weight H will move radially outward under theinfluence of centrifugal force to unwind the cable it from the pulley 72to rotate the latter in a direction to unscrew the shaft it from thescrew-threaded hole, and cause the lower end of this shaft to force thefinger lli downwardly, as shown by dash lines, and thus turn the shafts35 and 35 in a direction to increase the angle of inclination of thetrowel member-s. When the speed of the power unit is decreased, theangle of inclination of the trowel members ill will also be decreased.

Fig. 8 shows a further modification diagrammatically in which the trowelmembers 3i} are carried by brackets having longitudinal bores 32 whichare provided with rifiing. The brackets 8! are disposed on stationaryspirally-grooved rod-like supports 83 projecting radially from thehousing ill. The interengaging rifiing and spiral grooves of thebrackets 8i and supports 83 are employed for the purpose of causing thebrackets, together with their trowel members 80, to be tilted withrespect to the supports when the brackets are forced outwardly along thesupports under the influence of centrifugal force, when the power unit22 and housing 50 are rotating at a relatively high rate of speed.Springs 84 disposed between the brackets 85 and collars B5 on the endsof the supports 82 serve to return the parts to first position whereinthe trowel members Sil are tilted to a slight angle of inclination.

While I have herein shown and described my improved troweling machine asembodied in three preferred forms of construction, by way of example, itwill be understood that other modifications may be made in the structurethereof without departing from the spirit or scope of the invention.Therefore, without limiting myself in this respect, I claim:

1. In combination with a troweling machine of the type including aplurality of trowel members revolvable about a common axis and in whicheach of the trowel members is tiltable on an axis extending radially ofthe axis of revolution: a

variable speed power means connected to said trowel members forrevolving said trowel members; a tilting mechanism connected to each ofsaid trowel members for tilting the same; a governor connected to saiddriving means and having a member movable in response to variations inspeed of said driving means; and means interconnecting the movablemember of said governor with said tilting mechanism for tilting saidtrowel members to various angles in response to variations in speed ofsaid driving means.

2. In combination with a troweling machine of the type includin aplurality of trowel members revolvable about a common axis and in whicheach of the trowel members is tiltable on an axis extending radially ofthe axis of revolution: a variable speed power means connected to saidtrowel members for revolving said trowel members; a tilting mechanismconnected to each of said trowel members for tilting the same; agovernor connected to said driving means and having a member movable inresponse to variations in speed of said driving means; and meansinterconnecting the movable member of said governor with said tiltingmechanism for simultaneously tilting all of said trowel members tovarious angles in response to variations in speed of said driving means.

3. A trowelin machine including: a rotatable housing; radially extendingtiltable shafts on said housing; a trowel member carried by each of saidshafts; intermeshing gears on said shafts disposed within said housing;means on one of said shafts for turning said shaft to various angles tothereby simultaneously tilt all of said trowel members to acorresponding angle; variable speed p e me s con e ed 9 id housing e retating said housing and said trowel members; speed responsive meansconnected to said power means; and means connecting said speedresponsive means to all of said shafts for turnin said shafts to variousangles in response to variations in the speed of said power means.

4. A troweling machine including: a rotatable housing; radiallyextending tiltable shafts on said housing; a trowel member carried byeach of said shafts; intermeshing gears on said shafts disposed withinsaid housing; means on one of said shafts for turning said shaft tovarious angles to thereby simultaneously tilt all of said trowel membersto a corresponding angle; variable speed power means connected to saidhousing for rotatin said housing and said trowel members; speedresponsive means connected to said power means; a gear on each of saidshafts intermeshed with the gears of the other shafts; a crank on one ofsaid shaftsfor turning one of said shafts to thereby simultaneously tiltall of said trowel members; and plunger means interposed between saidspeed responsive means and said crank for actuating said crank todifferent angles in response to variations in speed of said power means.

JAMES O. HUFFMAN.

REFERENCES CITED The following references are of record in the

